1. Field of the Invention
A supply of make-up and combustion air is required for buildings with forced air heating from furnaces with a combustion chamber that burns fuel of natural gas or oil. Buildings are airtight rely on the make-up air supply to maintain a neutral or positive pressure so products from combustion don't enter the inhabited areas. While the forced air fan is operating it will draw in through the fresh air intakes upward of 180 to 125 cfm or what calculates into 10% of the make-up required for the building's particular furnace circulating system.
Where screens are required on air intakes supplying make-up air, the building code requires that the screens with less than ¼ inch. It's gross area shall be three times greater than the duct it serves. They shall be removable without any special tools and made of a none corrosive resistant material.
2. Description of the Related Art
In art, a device has been introduced for supplying make-up air to the forced air furnace circulating system as shown by Kogut, Jimmy A. U.S. Pat. No. 4,509,681, is known to use the same standard screen openings, ¼ inch, which is not removable for cleaning on the fresh air intakes. Screens of this nature are known to plug up with debris, freeze up with frost and snow, imposing difficulty on the air intakes to supply the make-up air, there by creating a negative pressure and allowing products of combustion into the inhabited areas, possibly at unsafe levels.
Studies show these air intakes develop a build up over time by allowing insects, mice, pollens, dust mites, allergens, and air borne bacteria to enter the furnace's circulating system, this accumulation and confinement has raised some health concerns.